This invention relates in general to a tubular member having splines formed thereon. More particularly, this invention relates to a tubular slip member having splines of multiple sizes for use in a vehicular driveshaft assembly. The tubular splines are provided for transmitting rotary motion and accommodating axial length changes, such as in a vehicular drive train system.
Drive train systems are widely used for generating power from a source and for transferring such power from the source to a driven mechanism. Frequently, the source generates rotational power, and such rotational power is transferred from the source to a rotatably driven mechanism. For example, in most land vehicles in use today, an engine/transmission assembly generates rotational power, and such rotational power is transferred from an output shaft of the engine/transmission assembly through a driveshaft assembly to an input shaft of an axle assembly so as to rotatably drive the wheels of the vehicle. To accomplish this, a typical driveshaft assembly includes a hollow cylindrical driveshaft tube having a pair of end fittings, such as a pair of tube yokes, secured to the front and rear ends thereof. The front end fitting forms a portion of a front universal joint that connects the output shaft of the engine/transmission assembly to the front end of the driveshaft tube. Similarly, the rear end fitting forms a portion of a rear universal joint that connects the rear end of the driveshaft tube to the input shaft of the axle assembly. The front and rear universal joints provide a rotational driving connection from the output shaft of the engine/transmission assembly through the driveshaft tube to the input shaft of the axle assembly, while accommodating a limited amount of angular misalignment between the rotational axes of these three shafts.
Not only must a typical drive train system accommodate a limited amount of angular misalignment between the source of rotational power and the rotatably driven device, but it must also typically accommodate a limited amount of relative axial movement therebetween. For example, in most vehicles, a small amount of relative axial movement frequently occurs between the engine/transmission assembly and the axle assembly when the vehicle is operated. To address this, it is known to provide a slip joint in the driveshaft assembly. A typical slip joint includes first and second members that have respective structures formed thereon that cooperate with one another for concurrent rotational movement, while permitting a limited amount of axial movement to occur therebetween.
One common type of driveshaft slip joint is known as a sliding spline slip joint. A typical sliding spline slip joint includes male and female members having respective pluralities of splines formed thereon. The male member is usually generally cylindrical in shape and has a plurality of outwardly extending splines formed on the outer surface thereof. The male member may be formed integrally with or secured to an end of the driveshaft assembly described above. The female member, on the other hand, is usually generally hollow and cylindrical in shape and has a plurality of inwardly extending splines formed on the inner surface thereof. The female member may be formed integrally with or secured to a yoke that forms a portion of one of the universal joints described above. To assemble the slip joint, the male member is inserted within the female member such that the outwardly extending splines of the male member cooperate with the inwardly extending splines of the female member. As a result, the male and female members are connected together for concurrent rotational movement. However, the outwardly extending splines of the male member can slide relative to the inwardly extending splines of the female member to allow a limited amount of relative axial movement to occur between the engine/transmission assembly and the axle assembly of the drive train system.
The male and female members have traditionally been forged or cast components, and the respective splines have traditionally been cut, rolled, or otherwise formed thereon. An alternative configuration for these spline members is to form the plurality of outwardly and inwardly extending splines directly onto the hollow tubular components of the driveshaft assembly. These tube-formed spline profiles are usually somewhat lower in weight than those of traditional forged or cast construction, but may require a longer mated engagement length. Additionally, the relative spline fits must be tight enough to ensure a stable lateral orientation yet, have sufficient clearance to slip without excessive force. While these tube-formed splines can provide adequate performance, the longer spline-form length often entails an increased processing time in order to provide the necessary fit tolerances for the assembled spline components. Thus, it would be desirable to provide a spline form configuration that can accommodate long spline lengths with reduced process cycle times. It would further be desirable to provide a spline form that provides a tight lateral fit, yet has a lower axial articulation force.